Patent GB-704757-A (GB)
Title: Improvements in tying machines for packages and the like
IPC: B65B13/22
Filed: 1950-06-06
Abstract: 704,757. Banding machines. POWER & SONS (BOX STRAPPING), Ltd., F. A., and CHEESEMAN, J. J. June 5, 1951 [June 6, 1950], No. 14041/50. Class 45. [Also in Groups XXII and XXIV] A wire tying machine has gripping means 21, 22 at opposite sides of the forming means 40, one of the gripping means 21 serving to hold the free end of the wire and the other gripping means 22, to hold the supply portion of the wire after the latter has been wrapped around the object to be tied, differential movement being imparted to the two gripping means to draw the wire into close contact with the object in tensioning the wire from both ends before it is tied. General features. - The machine is of the type in which wire is trained round a package by hand, the tensioning, cutting of the wire from the supply and tying of the ends then taking place automatically when a control mechanism 34 is depressed. The mechanism is mounted underneath the table top 24. Tensioning mechanisrn.-This comprises the first gripper 21 for the free end of the wire and the second gripper 22 for the supply end of the wire. When the control 34 is depressed the gripper 22 nears the end of its travel to the right end. The control mechanism 34 consists of a plunger 45 which acts against a spring 50 and which has a bevelled foot 54 engaging an arm 55, Fig. 3, the tip 57 of which is articulated so that it will transmit force downwardly but gives it an upward direction. The arm 55 is fixed to a shaft 56 which carries a blade 58 which can operate a one revolution clutch 39. The blade 58 and control mechanism 34 are both spring loaded and momentary actuation of the control mechanism is all that is needed to operate the clutch. The clutch consists of a member 64 having inwardly directed notches and which is continuously driven by an electric motor (not shown) and a member 67, Fig. 4, which slidably mounts a key 66 the key being urged radially into engagement with the notches of the member 64. In the rest position of the machine the key is held from engagement in the notches by a stop 68 on the blade 58. Movement of the blade by the control mechanism 34 allows the key to drop to engage a notch so that the member 67 is driven by the member 64. Towards the end of one revolution the key engages a surface 70 on the upper edge of the blade 58 and is raised out of engagement with the notch. When the key abuts the stop 68 the rotation of the member 67 is stopped the shock being cushioned by a coil spring 72 on the blade shaft 56. The member 67 is connected to a cam 76, Fig. 1, which actuates a pivotally mounted lever 79 resiliently connected to a lever 81 carrying the gripper 22. The resilient connection which is adjustable permits a predetermined tension to be applied to the wire. The cam moves the lever 79 to the right as shown in Fig. 1 to tension the wire and allows it to return to a slight extent to the left to be held by a detent mechanism 32, consisting of a spring urged pawl 90 which engages a recess 96 in the top of the lever 79. The pawl is attached by adjustable linkage to a resetting lever 101, Fig. 2, operated by a cam 105 which is driven through a one revolution clutch 38 identical in construction to the clutch 38. When the clutch causes the cam to revolve the lever 101 lifts the pawl 90 from the recess 96 thus allowing the gripper 22 to move to the left under the tension in the wire. When the gripper mounting lever 81 nears the end of its guide slot the gripper jaws are opened to admit the end of the wire. The gripper has a bottom opening slot 43, Fig. 6, and after the wire has been trained round a package it is pulled into this slot where it is gripped by a pivoted jaw 109. When it is pulled into the slot the wire engages an arm 119 of a release lever 116 and so causes a second arm 117 to be removed from against a stop 118. The release lever then slides axially under pressure of a spring 120 until stopped by a pin 211. The movement of the arm 117 from the stop allows a plunger 114 to move axially to engage the stop and this movement allows the jaw 109 to close on the wire. The plunger 114 remains in its extended position during the movement of the gripper to the right but this movement allows the arm 117 to drop back to its original position in front of the plunger, and when the gripper returns to the left and before it reaches the limit of its travel the arm 117 engages the stop 118 and so causes the plunger 114 to open the jaw to release the wire. When the gripper 22 nears the end of its travel to the right it operates the clutch 38. This is caused by an abutment 125 on the lever 79 striking an arm 126 on a shaft 127 which carries a blade 129 similar to blade 58 of clutch 39. The clutch 38 drives a main cam-shaft 135, Fig. 2, and an auxiliary cam-shaft 137 which control the gripper 21 and the wire separating, cutting and twisting mechanisms which are similar to those described in Specification 523,786. The gripper 21 is mounted on a shaft 138 to which an axial sliding motion to tension the wire is given by an arm 147 which is resiliently connected to a bell crank 145 in turn actuated by cams 140 and 141 on shafts 135, 137 so that the tensioning takes place after gripper 22 has tensioned the other end of the wire. Wire separating, cutting and twisting mechanism. -When the wire has been tensioned two separators 25 are moved forward to separate the free and supply ends of the wire from the loop around the package. These separators have wedge shaped ends and are resiliently connected to a yoke 154 which is moved through an arm by cams 156, 157, on shafts 135, 137. The separators are moved forwardly until the free and supply ends of the wires snap behind a cutting edge on each separator, the separators are then retracted and the wires are cut between the edges and fixed cutters. After the ends of the wire around the package have been twisted the separators are again projected forwardly and a face on each ejects the completed tie from the twisting pinion. Before the wires are cut a wire retainer 31 is moved forward through a cam 166 on shaft 135 to engage the portion of the wire between the gripper 22 and the adjacent separator 25. The retainer has a fixed jaw and a spring closed jaw so that it automatically grips the wire. The twisting pinion 40 has a slot which is directed downwardly in the rest position of the machine and it is moved in a clockwise direction through several revolutions and a half revolution and stops with its slot upwardly ; the wires are cut in this position and the pinion is rotated a further half revolution and is then reversed and rotated backwards through a quarter of a revolution to relieve torque on the wire. The pinion stops with its slot horizontal so that the tie can be ejected by the separators. The pinion is moved through a gear train by a quadrant 172 which is moved by cams 173, 174 on shafts 135, 137. When the wire has been cut the gripper 21 is opened by an arm 179 as disclosed in Specification 523,786 to release the wire tailing and the jaws are held open by a detent. The gripper is then moved angularly through rotation of the shaft 138 by a cam 181 through linkage 139, to swing the gripper out of axial alignment with the twisting pinion, the tailing being removed by a guide on the left hand side of the twisting pinion against which it abuts during this movement. The gripper is then moved to the left by the arm 147 and 145 past the pinion 40 to the position of the wire retainer 31. The shaft 138 is rotated clockwise to swing the gripper 21 back into axial alignment with the pinion 40 and adjacent the wire retainer 31 and the detent is released to allow the gripper to grip the wire by means of a lever which is operated by a spring loaded abutment on the twisting pinion operating quadrant 172 when this moves in an anti-clockwise direction. The shaft 138 is then moved angularly by cam 181 to pull the wire from the retainer 31 and to the left until the gripper 21 regains its original plane after which it is swung back into its original position and threads the wire into the slot. The twisting pinion is meanwhile rotating to regain its initial position with the slot facing downwardly. Since the wire is not in tension it is prevented from dropping out of the slot by guides on the right hand side of the pinion. The guide is spring loaded so that when the supply portion of the wire is trained round the package it gives to allow the wire to pass into the twisting pinion. Operation.-In the rest position the end of the wire is threaded through the twisting pinion 40 and is held by the gripper 21. The operator trains the wire by hand in a loop around the package and brings the supply end into slot 43 in gripper 22 where it is gripped by jaw 109. In doing this the supply end of the wire also enters the slot in the twisting pinion. The control 34 is depressed which causes clutch 39 to rotate through a single revolution. This rotation moves gripper 22 to the right to draw the wire around the package and apply tension to the supply end of the wire. The gripper is locked in its right hand position by detent 90. Near the end of its movement the gripper mounting lever operates the one revolution clutch 38 which causes camshafts 135, 137 to make one revolution. The camshafts move gripper 21 to the left to tension the free end of the wire, the separators 25 are projected forward to separate the ends of the wires lying side-by-side in the twister pinion slot and the wire retainer 31 is projected forward to engage the supply side of the wire. The twisting mechanism then ties the wire and stops with its slot upwards. The detent 90 is unlocked to release gripper 22 and the separators are retracted to cut the wire, the twister pinion rotates half a turn to over-twist the wire and then rotates backwards a quarter turn so that the slot is horizontal and facing outwardly. The tie is then ejected by forward projection of